Charmer,
That seems like very good price, but how do you know it's a '68 without the date codes. I just went through the whole ID research process on mine with a lot of help here. There should be some sort of date code on the driver's side of the block stamped just above the
oil pan, near the
oil filter mount. The consensus of the FE experts here was that, absent a code on the pass. side of the block (denoting which car it was installed in), it's a "service" block, as is mine.
But, no matter what it is, that appears to be a very good price for a healthy SO.